Do Kids' BPA Levels Predict Future Disease?

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Children and adolescents with high levels of urinary bisphenol A (BPA) showed evidence of low-grade albuminuria, which may have implications for the later development of kidney and cardiovascular disease.

Note that longer-term studies will be needed to determine whether the low-grade albuminuria observed in this study actually translates into the metabolic syndrome and renal dysfunction.

Children and adolescents with high levels of urinary bisphenol A (BPA) showed evidence of low-grade albuminuria, which may have implications for the later development of kidney and cardiovascular disease, researchers suggested.

In a fully adjusted model, children and teens in the highest quartile of urinary BPA had an albumin-to-creatinine ratio that was 0.91 mg/g higher than those in the lowest quartile (P=0.007), according to Howard Trachtman, MD, and colleagues from New York University School of Medicine in New York City.

And in an analysis modeling the albumin-to-creatinine ratio as a continuous variable, a 0.28 mg/g elevation was seen for every log-unit-greater level of urinary BPA (P=0.030).

"Given that endothelial dysfunction manifests as low-grade albuminuria, our study raises the concern that BPA exposure during childhood may contribute to early atherosclerotic changes in children and adolescents, similar to the development of angiographically confirmed coronary artery atherosclerosis associated with BPA exposure in adults," they stated.

In the U.S., BPA is used in the interior coatings of aluminum cans to prevent corrosion, as well as in dental sealants and thermal paper receipts, and exposure is nearly universal.

In addition, animal studies have found evidence of oxidative stress in the exposed kidney, and a study of Chinese adults found that the presence of BPA in urine correlated with the degree of low-level albuminuria, or protein leakage into the urine, signifying early renal damage.

Furthermore, the presence of urinary BPA also has been linked in cross-sectional studies with cardiovascular disease and diabetes in adults.

But the effects of BPA exposure in children have not been examined, even though youngsters tend to be particularly susceptible to environmental exposures.

So Trachman's group analyzed data from a sample of the 2009-2010 National Health and Nutrition Examination Survey, including 710 participants ages 6 to 19 who had urinary BPA and creatinine measurements.

Levels of BPA were divided into quartiles, with the lowest quartile being below 1.1 ng/mL and the highest quartile exceeding 4.3 ng/mL.

Albumin-to-creatinine ratios also were divided into quartiles, with the lowest being less than 4.3 mg/g and the highest being greater than 9.34 mg/g.

Lower levels of urinary BPA were found in children who were older and in higher socioeconomic strata, the researchers noted.

In a model adjusted only for BPA concentration in the urine, children whose urinary BPA was in the highest quartile had a 1.77 mg/g higher albumin-to-creatinine ratio than those in the lowest quartile (P=0.006).

There also was a 0.50 mg/g rise in this ratio with each log unit increase of BPA in the urine (P=0.045).

The adjusted model also considered sociodemographics, other environmental exposures, and conditions such as blood pressure, cholesterol, and insulin resistance.

No association was seen for albuminuria and other environmental phenols.

"These findings broaden the array of adverse effects associated with [urinary] BPA, for which the evidence is strongest for decrements in neurodevelopmental and fertility outcomes, and increases in obesity and cardiovascular disease," the researchers observed.

Longer-term studies will be needed, however, to determine whether the low-grade albuminuria observed in this study actually translates into the metabolic syndrome and renal dysfunction.

Additional vascular studies also could help confirm the researchers' hypothesis that BPA exposure is associated with endothelial dysfunction.

Limitations of the study include its observational design, a lack of information on exercise and diet, and uncertainty as to whether estimates of urinary BPA reflect current or past exposures.

Nonetheless, the findings of this study warrant increased regulatory attention to the use of BPA and the potential for adverse health consequences, according to the researchers.

The study also suggests the need for reconsidering the concept of low-grade albuminuria "to an approach that recognizes the role of environmental chemical factors that may independently impart the risk of endothelial dysfunction and future cardiovascular disease," they concluded.

The authors reported no conflicts of interest.

Reviewed by Robert Jasmer, MD Associate Clinical Professor of Medicine, University of California, San Francisco and Dorothy Caputo, MA, BSN, RN, Nurse Planner

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